The present invention relates generally to microelectronic packaging. More specifically, but without limitation thereto, the present invention relates to insulating bonding wires to avoid package defects resulting from short circuits between adjacent bonding wires.
Bonding wires are used in microelectronic packaging to connect bond pads of a chip or die to package leads. The bonding wires are typically made of gold or aluminum and have a thin diameter of only about 30 microns.
As chip size becomes smaller as a result of improvements in manufacturing and chip density, and as the size of the microelectronic package increases, the bonding wires have to be made longer and spaced more closely together. The increased length and closer spacing increases the probability that adjacent bonding wires will deviate from their intended position and come into electrical contact with one another, resulting in a defective package.
Another problem with current techniques for attaching bonding wires is that wires may not cross each other to avoid coming into electrical contact with one another and have to be attached in an array, one after another, restricting the versatility of the microelectronic package.
The present invention advantageously addresses the needs above as well as other needs by providing a method and apparatus for insulating a bonding wire.
In one embodiment, the invention may be characterized as a method for insulating a bonding wire that includes the steps of attaching a bonding wire to a bond pad; coating the bonding wire with an insulating liquid while drawing the bonding wire through a bond tool from the bond pad to a package lead; and attaching the bonding wire to the package lead.
In another embodiment, the invention may be characterized as an apparatus for insulating a bonding wire that includes a dispensing tool coupled to a bond tool for forming a coating of an insulating liquid on a bonding wire after the bond tool attaches the bonding wire to a bond pad.